Lehigh Southwest Cement discharges worry neighbors

ENVIRONMENT

Kelly Zito, Chronicle Staff Writer

Published 4:00 am, Tuesday, December 21, 2010

Neighbors of a historic South Bay cement plant are urging authorities to block plans for extending the facility's life for 20 years, arguing the operation spews potentially harmful amounts of mercury into the air.

Santa Clara County's Board of Supervisors is reviewing a long-term permit for the Lehigh Southwest Cement Co. plant in Cupertino, which hopes to excavate a second limestone pit when its existing quarry is tapped out within the next decade.

But hundreds of residents who live near the 3,500-acre site - regularly listed as one of the top emitters of noxious gases in the Bay Area by air regulators - say the industrial business no longer belongs in an area now packed with homes, schools and parks.

This evening, the Cupertino City Council is expected to weigh in on a smaller issue related to the expansion: whether to allow the Dallas company to continue using an 89-acre parcel to dispose of rock and other debris.

Mining has occurred on the property since the late 1800s. But it was famed shipbuilder and industrialist Henry Kaiser who began a large-scale business in 1939 - using a rich limestone deposit to supply material for Shasta Dam. Today, the plant supplies the Bay Area with half of the cement used in new homes, roads, hospitals and bridges.

"We've had a quarry and cement plant there for a long time, and it's made big contributions to the growth of the county," said Bill Almon, founder of the watchdog group Quarry No. "But this is not the place to dig a new pit. When Kaiser started this, it wasn't a populated area and we didn't know what we know about mercury."

Almon and others think the plant should be permitted to operate until the current quarry is exhausted; then it should be shut down.

Metal vaporizes into air

Now known as a potent neurotoxin, mercury occurs in high concentrations in the limestone buried in the hills above Cupertino. When the rock is fired in the cement plant's enormous kilns, the metal vaporizes and travels through the air.

Company officials say their discharges are closely tracked by local, state and federal air and water regulators and, to date, have fallen below thresholds considered unsafe.

What's more, Lehigh representatives regularly meet with city and public groups to answer questions and address concerns, said Tim Matz, director of environmental affairs at the company's headquarters in Texas.

In fact, Matz said, the company this summer installed equipment that has cut mercury emissions 30 percent - well ahead of new federal regulations that call for drastic cuts by 2013.

"We're taking early actions and making an effort to reduce emissions now," Matz said.

According to the U.S. Environmental Protection Agency's annual Toxic Releases Inventory, Lehigh Southwest discharged anywhere from 208 and 585 pounds of mercury between 2000 and 2009.

But Almon and others argue those numbers are misleading because, for years, the plant used calculations that underestimated the amount of mercury in its emissions.

Bay Area regulators confirmed the company has recently revised its mercury emission levels upward to comply with new federal standards. But they still do not rise to harmful concentrations, said Brian Bateman of the Bay Area Air Quality Management District.

Measuring pollutants

Nevertheless, the agency installed monitoring equipment in September at a community center about three-fourths of a mile from the plant. The gear will measure mercury and other air pollutants for at least one year.

"We're trying to make sure the emissions don't have significant impacts on people's health," Bateman said.

It is the second time in two years that concerns about air pollution near the Lehigh plant have prompted regulators to test air quality there. For several months in 2009, the U.S. Environmental Protection agency analyzed air at Stevens Creek Elementary School for hexavalent chromium, a carcinogen. The September report found the chemical did not occur at levels harmful for either short or long periods of exposure.